Sub-season model

X₁

X₂

X₃

X₄

X₅

R²

Spring

B3/B1

B4/B7

B5/B4

B7/B5

^*

0.83

Mid-summer

B5

B7

B2/B4

B5/B3

^*

0.64

Late-summer

B1

B2/B5

B3/B5

B4/B7

B5/B4

0.91